Technical Field
A memory managing method, a memory control circuit unit and a memory storage apparatus are provided.
Description of Related Art
The growth of digital cameras, mobile phones, and MP3 players has been rapid in recent years. Consequently, the consumers' demand for storage media has increased tremendously. A rewritable non-volatile memory is one of the most adaptable memories for portable electronic products such as laptop computer due to its data non-volatility, low power consumption, small volume, non-mechanical structure and high read/write speed. A solid state drive (SSD) is a memory storage apparatus which utilizes a flash memory module as a storage medium. For these reasons, the flash memory has become an import part of the electronic industries.
In general, the rewritable non-volatile memory module usually includes a plurality of physical erasing units, and each of the physical erasing units includes a plurality of physical programming units. Particularly, the physical erasing unit in the rewritable non-volatile memory module has a limited number of times in terms of an erase count. For example, the physical erasing unit may be worn out after experiencing an erase operation for over ten thousand times. When one specific physical erasing unit is worn out, error bits may be generated while programming (or writing) the data into that specific physical erasing unit. In severe case, it also leads to adverse effects such as data loss or data storage failure.
In addition, after the data stored in one specific physical programming unit in one physical erasing unit is repeatedly read for multiple times (e.g., with a read count from hundred thousand times to million times), it is highly possibly that the data stored by the specific physical erasing unit may generate error bits or may be lost due to applied read voltage. Worth yet, the data stored in other physical programming units of the same physical erasing unit may also generate error bits or may be lost. This kind of phenomenon is commonly referred to as “read-disturb” by person with ordinary skill in the art.
Because the read-disturb and waring phenomenons will occur in the rewritable non-volatile memory module with uses of the physical erasing unit over time, manufacturers must develop various memory managing methods to overcome those phenomenons, so as to effectively reduce a wearing probability and control an occurrence probability of the read-disturb for the physical erasing unit.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.